Thursday 1 - infectious disease Flashcards
Big three symptoms of CNS infections?
Fever, headache, altered mental state.
Some organisms that can cause memengitis, bacterial and viral.
Most common bacterial sources by age? (young and adult)
Non-viral (serious) - most common - Neisseria meningitidis (most common in younger people), Streptococcus pneumonia (~75% in adults), haemophilus influenza.
less common - Rickettsia, Mycoplasma, Listeria monocytogenes
viral: Herpes, enterovirus, arbovirus, rabies
Some organisms that can cause encephalitis.
Fungal - more chronic
Herpes
5 non-infecitous causes of “fever, headache, altered mental state”
Subarachnoid hemorhage, inflammatory disease (lupus), Neoplasia, metabolic (ammonia build up), drug (NSAID)
3 Types of CNS infections (Broad)
meningitis, encephalitis, abscess
Where is meningitis in the brain
subarachnoid space
Where is encephalitis in the brain
diffuse parenchyma
Encephalopathy
refers to diffuse cerebral dysfunction without inflammation usually due to toxin, or metabolic product
What example of meningitis in class was transmitted via the respiratory system?
Neisseria meningitidis
Disease from class the had a 25% mortality rate and had a “major” outbreak in 2014
Listeria monocytogenes meningitis
Best empiric antibiotic for meningitis, how much greater do you want to concentration than the MIC in order for it to be bacteriocidal?
3rd gen cephalosporin (+ Ampicillin?)
10 times the MIC
What is often included with the antibiotic in encephalitis in order to decrease inflam?
dexamethasone
mech of Ceftriaxone (3rd gen cephalosporin)
Ways that the bacteria can become resistant to it?
inhibition of transpeptidation of peptidoglycan
Resistance can occur if the bacteria inactivates the drug via beta-lactamases
General properties of Listeria monocytogenes
3 symptoms from listeria meningitis, and one common menigitis symptom not seen in the case in class
Gram +
Rod
Fever, headache, diarrhea
No nuchal rigidity
What is the definitive therapy for Listeria monocytogenes?
Ampicilin + Gentamicin
genta - aminoglycoside -(ribozyme inhibitor)
4 main (non culture) things you look for in lumbar puncture for suspect meningitis.
Which is prominent in which type of meningitis?
WBC count - will be high
WBC diff. - high PMN if bacterial, high lymphocyte if viral, fungal, or tuberculous
protein - will be high
glucose - will be low (especially in bacterial infection, tuberculous infection)
Main symptoms in viral meningitis
Fever, headache, photophobia
Stiff neck less common with viral meningitis
Most common type of virus seen in Meningitis
What type of virus is it? RNA or DNA?
enterovirus/picornavirus (coxsackie, ECHO, polio)
RNA virus
Major endotoxin of Neisseria meningitides. what does it mimic in humans?
What is one clinical sign about this type of meningitis that is not as often seen in other bactrerial types?
LOS (lipooligosacchride)
mimics sphingolipids in the brain
purpuritic skin rash
Things about hemophilus influenza type b with respect to meningitis
occurs in:
infection can be followed by this debilitation:
type b reffers to:
In unvaccinated kids
hearing loss
B capsular polysaccharide - cap around the bacteria helps it into the brain
TORCH infections
Who are they dangerous to?
two organisms that cause them
serious fetal consequences
Meningitis: Group B strep, E. coli
Group B streptococcus General
GI and urinary tract flora
vertical transmission to infact
more common in african americans
pregnant women screened with 25% as carriers and given penicillin G and prophylactic
3 organisms that you are worried about kids getting infected with (meningitis) but not usually adults
GBS (group b strep)
E. Coli
Listeria
Chronic meningitis organisms
spirochetes, mycobacterium tuberculosis, fungi (cryptococcus, coccidioides, candida)
Amphotericin B
mech
spectrum
distribution in brain
averse
Binds ergosterol, making holes in fungal membrane
broad spectrum
Liposomal, crosses BBB
Nephrotoxic because it binds cholesterol, amphoTERRIBLE.
Flucytosine
mech
spectrum
converts to 5-FU in fungi
spec is narrow - yeast
Azoles
mech
spectrum
binds fungal p-450
systemic mycoses
